In the study of a therapeutic agent, many drugs have been found by a method using an in vitro model. However, some drugs have a low bioavailability and have limited therapeutic usefulness. In order to avoid these problems, there have been known means of chemically modifying a compound to form a prodrug.
A benzothiophene derivative, which is typified by 1-(3-(2-(1-benzothiophen-5-yl)ethoxy)propyl)-3-azetidinol, has a neuroprotective activity, a nerve regeneration promoting activity and a neurite outgrowth promoting activity and is a useful compound as a therapeutic agent for central and peripheral nerve diseases (Patent Document 1). However, the benzothiophene oxide derivative described in the present application has never been known before.